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It started when two canine scientists decide to become pen pals in an era of digital media...

Thursday, 3 January 2013

Thinking laterality: steps, jumps and wonder-whorls

Happy New Year Julie!Thank you for all that great info about canine noise sensitivity and what can be done. I'm very happy to report my two dogs got through the fireworks without any obvious anxiety this year.I'm so pleased you raised the topic of laterality in dogs.

You mentioned the work of DrNick Branson, who I have been fortunate to work with in our Australian working dog welfare research, along with Professor Paul McGreevy, who we have both mentioned before. One of Paul's postgraduate students -- Dr Lisa Tomkins -- recently received her PhD after progressing this field of study significantly. Lisa and I met a few years back when we were studying different Guide Dog populations. I thought I'd tell you brieflyabout her research and how it connects laterality and working dogs. I also thank Lisa for sending me through some of her images to help in illustrating her work.It's no mean feat to try and summarise many years of dedicated PhD research without selling it short, but I'll do my best! Lisa looked at a range of physiological, physical and behavioural traits relating to Guide Dog success during the course of her PhD. As part of this, her research uncovered some new and particularly fascinating results regarding the expression of motor, sensory and structural laterality.

First-stepping (Motor)One of the problems with the Kong™ test (see picture above), that has been used as a benchmark test of laterality, is that hunger and/or motivation to feed can be confounding factors. It can also take up to four hours to collect the requisite 50 observations per dog.

Lisa's research demonstrated that a novel and innovative first-stepping test (that recorded the first foot moving forward after standing still with both forelegs level) overcame the issues of food involvement and proved much quicker, with 50 observations collected in under 20 minutes.Her results showed a stronger bias demonstration that the previously used Kong™ test and the majority of dogs tested showed a preference to the right (46%), rather than the left (30%) or testing as ambidextrous (24%). This test showed good repeatability and reliability, offering a robust, simple and relatively quick test to measure paw preference, demonstrating motor laterality.

Another innovative test developed during Lisa's research was the sensory jump test. Many variables were recorded, such as launch/landing paw, jump clearance height, approach distance, jump type and success in clearing the obstacle.But this was not a simple paw preference test. Oh no! It was actually designed to test eye preference in a jumping task, so dogs were tested over the jump 10 times under three different ocular conditions.

source: Dr Lisa Tomkins

source: Dr Lisa Tomkins

The results showed that dogs with the left monocular vision treatment demonstrated significantly compromised jump kinematics on their first jump set. Whereas the right monocular vision treatment dogs performed similarly to the binocular vision dogs.

There was no association between eye preference and motor laterality preferences. This was consistent with findings in primates and horses and indicates that the sensory and motor lateralisation rely on different mechanisms and occur on at least two different levels of neural organisation within the brain.

Hair whorls (Structural)Hair whorls are a physical feature of hair patterning in the skin that can feature left-right asymmetry. In previous human research, correlations had been demonstrated between hand preference and hair whorls. Studies in other animals (cattle and horses) showed correlations between hair whorls and behavioural traits.

Lisa sought to bring these elements of hair whorls, behaviour and laterality together in her research focussed on Guide Dogs.As no one had previously looked at hair whorls in dogs, she first had to develop a way to identify and measure the hair whorls found in dogs. She located positions where most dogs showed hair whorl patterning and in which population trends for direction (clockwise vs. counter-clockwise) were evident.Further research showed the first evidence of an association between structural asymmetry (the presence and direction of hair whorls) and sensory lateralisation (the sensory jump test). There was also an association found between structural and motor (paw preference) laterality.Interestingly, dogs with clockwise chest whorls were more likely to be 'right-pawed'.

Dr Lisa Tomkins' research has provided fellow researchers with important insight into the different expressions of motor, structural and sensory lateralisation in domestic dogs. She has certainly added significantlyto the landscape for future work in this area of study.

The expressions of laterality investigated have demonstrated associations that relate to behavioural traits that can determine/predict Guide Dog success.

Lisa's research determined that dogs with a significantly increased likelihood of Guide Dog training success demonstrated:

These objective measures of features present from an early age (especially physical traits like hair whorls) could prove helpful in identifying dogs most likely to succeed at Guide Dog work, improving the efficiency of programs dedicated to producing working dogs.

Prefer to watch it?For a really neat (<7min) summation of most of Lisa's PhD research,
check out this great short clip from the Australian ABC's national science program, Catalyst:click here